For several years in a row, Cyber Monday has been the busiest online shopping day of the year. Online businesses offering good deals are stretching that into Cyber Weekend and Cyber Week, but experts warn of scammers.

In this 2008 photo, an Amazon.com employee grabs boxes off the conveyor belt to load in a truck at Amazon's Fernley, Nev., warehouse. Cyber Monday is expected to be the biggest online shopping day of the year for the third year in a row.

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Experts say “Super Saturday” (Dec. 20) is likely to be the busiest single shopping day of the year.

But “Black Friday” – which has become a five-day consumerist extravaganza of what are furiously and incessantly advertised as good deals – has given a running start to a holiday spending season expected to top $616 billion.

“Just like Black Friday, you need a strategy for Cyber Monday,” the company declares. “However, since many Cyber Monday sales aren't revealed until the weekend before or the actual day of, there isn't a lot of time to plan. You need reinforcement – a way to find the best deals quick. Fortunately, you can download several apps to your smartphone or tablet to save time and money.”

As a bonus app, DailyFinance points to CyberMonday.com, which highlights the best deals from more than 800 online retailers.

Time.com points to the “Top 10 gadgets of 2014.” Number two on the list is something called the “SmartThings Starter Kit” ($200), which “connects inanimate objects in your house to your phone.”

“Use it to attach sensors to your home and program smart objects from locks to crockpots and soon you’ll be living like the Jetsons,” Time explains.

There are many such lists out there, but our personal favorite is “Brad’s Cyber Monday” (no relation), “Home to all the best online shopping deals and coupon codes of Thanksgiving Weekend and Cyber Monday 2014.”

For many online shopping powerhouses – Amazon included – Cyber Monday has stretched into “Cyber Weekend.” Amazon, in fact, is calling it “Cyber Week” with this come-on: “We're bringing you thousands of deals throughout the week. Some Cyber Monday 2014 deals are in limited supply, and all will go quickly – but don't worry if you miss one, because we'll keep adding new ones, as often as every ten minutes, all week long.”

Shoppers must be lining up there in unusual numbers, because the Amazon site was cranking slower than usual Sunday afternoon.

With all this online shopping, experts say consumers must be more than a little vigilant for scammers.

“They know it's Cyber Monday. They know people are out there shopping and they're going to do what they can to try and lure you in,” Michael Kaiser with the National Cyber Security Alliance told CNN.

Mr. Kaiser says consumers must be proactive and take precautions. “If they take those common-sense measures – they update their software, they put in things like two-step verification or multi-factor authentication – those are things that are in their control.”